Fibrous structures, such as paper webs, are produced by a variety of processes. For example, paper webs may be produced according to commonly-assigned U.S. Pat. No. 5,556,509, issued Sep. 17, 1996 to Trokhan et al.; U.S. Pat. No. 5,580,423, issued Dec. 3, 1996 to Ampulski et al.; U.S. Pat. No. 5,609,725,issued Mar 11, 1997 to Phan; U.S. Pat. No. 5,629,052, issued May 13, 1997 to Trokhan et al.; U.S. Pat. No. 5,637,194, issued Jun. 10, 1997 to Ampulski et al.; and U.S. Pat. No. 5,674,663, issued Oct 7, 1997 to McFarland et al., the disclosures of which are incorporated herein by reference. Paper webs may also be made using through-air drying processes as described in commonly-assigned U.S. Pat. No. 4,514,345, issued Apr. 30, 1985 to Johnson et al.; U.S. Pat. No. 4,528,239, issued July 9 to Trokhan, 1985; U.S. Pat. No. 4,529,480, issued Jul. 16, 1985 to Trokhan; U.S. Pat. No. 4,637,859, issued Jan. 20, 1987 to Trokhan; and U.S. Pat. No. 5,334,289, issued Aug. 2, 1994 to Trokhan et al. The disclosures of the foregoing patents are incorporated herein by reference.
Foreshortening of a fibrous webs may be used to increase the web's caliper, absorbency and softness. Foreshortening refers to reduction in length of a dry web, resulting from application of energy to the web. Typically, during foreshortening, rearrangement of the fibers in the web occurs, accompanied by at least partial disruption of fiber-to-fiber bonds. As a result of foreshortening, micro-folds, commonly called "crepe" are formed in the web.
It has been discovered that the increase in caliper, or bulk, of the foreshortened web may further be achieved by relaxing, at least partially, the crepe in the web. It has been further found that the crepe can be relaxed in pre-selected portions of the web such that the rest of the web, not affected by the crepe relaxation, retains the quality of the foreshortened web.
Accordingly, it is a subject of the present invention to provide a novel process for increasing bulk of the foreshortened web by relaxing the web's crepe in the selected portions of the web. It is another object of the present invention to provide an apparatus for increasing bulk of the foreshortened web by relaxing the web's crepe in the selected portions of the web.